Johnston



1955 E. w. JOHNSTON APPARATUS FOR LAPPING WIRE-DRAWING DIES Filed Sept. 12. 1950 2 Sheets-Sheet l FIE-C'J- Inventor:

Jan. 11, 1955 E, w. JOHNSTON APPARATUS FOR LAPPING WIRE-DRAWING DIES 2 Sheets-Sheet 2 Filed Sept. 12. 1950 United States Patent APPARATUS FOR LAlillsNG WIRE-DRAWING Earl W. Johnston, Worcester, Mass., assignor to United States Steel Corporation, a corporation of New Jersey I Application September 12, 1950, Serial No. 184,471

9 Claims. (Cl. 51-46) This invention relates to the finishing of wire-drawing dies and, in particular, to apparatus for finishing the bearing and the entrance and relief cones of the die opening in a single operation and automatically lifting the lapping pin from the die when the operation has been completed.

Wire-drawing dies must be finished to a high degree of accuracy. They are used in large numbers and their cost is a substantial factor in the final cost of drawn wire. It is accordingly desirable to finish the dies on automatic machines as rapidly as feasible. The object of my invention, therefore, is to provide an improved apparatus for finishing the opening originally formed in a die blank and refinishing the opening in worn dies to a larger size. I have invented a novel apparatus for this purpose having important advantages over machines and practices known heretofore.

In a preferred embodiment and procedure according to my invention, I mount the die in a holder journaled for rotation on a support. The support is positioned below a lapping spindle and tiltable about an oif-set pivot so as to raise and lower the die and tilt it when lowered. The spindle has a lapping pin extending downwardly thereof with terminal and intermediate portions of different di ameters of which the former is effective for working simultaneously on the reducing and relief cones of the die when it is lowered and the latter for finishing the bearing of the die to precisely the desired size and shape when the die is raised. The spindle is journaled for reciprocation as well as rotation. I provide automatic means actuated by descent of the spindle on finishing the bearing of the die to the desired size, effective to lift the pin out of engagement with the die. I also provide means to prevent such operation as a result of descent of the spindle when the die is in its lower tilted position.

A complete understanding of the invention may be obtained from the following detailed description and explanation which refer to the accompanying drawings illustrating the present preferred embodiment. In the drawings,

Figure l is a partial front elevation showing one end of the apparatus with parts omitted for clearness;

Figure 2 is a transverse section taken along the plane 11-11 of Figure l with parts in alternative positions;

Figure 3 is a section through a die showing the relation of the lapping pin thereto when the die holder is raised for finishing the bearing; and

Figure 4 is a similar view showing the relation of the lapping pin to the die when the die holder is lowered for finishing the reducing and relief cones.

Referring now in detail to the drawings, the apparatus there shown is mounted in a frame composed of a bottom bar 11 having posts 12 upstanding thereon and vertically spaced horizontal bars 13, 14 and 15 carried on the posts. The frame is adapted to rest on a table 16 or other suitable base. Spaced horizontal plates 17 and 18 are also carried on the posts 12 being disposed inwardly thereof adjacent bottom bar 11 as shown in Figure 2, and secured to end plates 17a extending inwardly from the posts.

A die-holder supporting plate 19 is disposed in a vertical plane against bar 15 and plate 17 and has an arm 20 extending laterally therefrom pivoted to the bar 15 on a pin 21. As shown in Figure 2, arm 20 extends inwardly of bar 15 and downwardly behind it. The supporting plate 19 is provided with vertically spaced bear- "ice ings 22 in which a shaft 23 is journaled for rotation. A die-holder 24 is mounted on the upper end of the shaft and has a socket in its upper base adapted to receive a die such as that indicated at 25. As shown in Figures 3 and 4, the die 25 comprises a nib 26 of hard metal imbedded in a block or casing 27 of steel. A pulley 28 on shaft 23 permits the latter to be driven by a belt 29, the plate 19 having a window 30 to admit the belt. Shaft 23 is slidable in bearings 22 and is held in proper position by an adjusting screw 31 threaded through an angle bracket 32 secured to plate 19.

The lower portion of plate 19 has downwardly projecting horns 33 adapted to be engaged by a cam 34 whereby the plate is periodically oscillated through a limited angle, i. e., it is raised to the position shown in Figure 1 and then permitted to swing downwardly by gravity about pin 21 to a lower position in which the shaft 23 and holder 24 are at a slight inclination to the vertical. Cam 34 is adjustably secured by a screw 34a to a shaft 35 journaled in plates 17 and 18. A longitudinal shaft 36 journaled in the end plates 17a connecting the plates 17 and 18 has a worm thereon meshing with a worm wheel 37 on shaft 35. The drive for shaft 36 will be explained later.

A vertical spindle 38 is journaled in bearings 39 seated in holes 40 in horizontal bars 13 and 14. Each bearing has a flange 41 resting on the upper face of its supporting bar. The holes 40 are larger than the bearings 39 permitting slight adjustment of the bearings in a horizontal plane for a purpose which will appear later. The bearings are held in adjusted position by screws 42. The holes in the flanges 41 through which the screws extend are larger than the shanks of the screws to permit the desired adjustment.

The spindle 38 has a chuck 43 at its lower end adapted to receive a lapping pin 44. The pin has a cylindrical working portion or shank 44a adapted to work on the bearing of the die-nib 26 as shown in Figure 3. The pin also has a reduced extension or tip 44b adapted simultaneously to work on the reducing and relief cones of the die-nib when the die is tilted and lowered as shown in Figure 4. Spindle 38 is provided with a drive pulley 45 between bearings 39 so that it may driven by a belt 46.

It will be evident that the die-holder 24 and the spindle 38 constitute a couple or unit for machining by lapping. Any desired or suitable number of such couples or units may be mounted side-by-side in frame 10. Since additional couples or units would be identical with that shown, the illustration of the latter is not repeated in the drawings. The end of frame 10 opposite that shown is identical therewith but of opposite hand.

Spindle 38 is slidable in bearings 39. When there is no die in holder 24 or when plate 19 has swung down to its lower position, the spindle descends until the pulley 45 rests on a lever 47, the forward end of which is bifurcated to straddle the spindle. The pulley thus serves as a shoulder or thrust collar as well as a driving member. The lever 47 is pivoted on a bracket 48 secured to a plate 49 extending inwardly from the upper bar 13. A shaft 50 journaled in bearings 51 carried on the bar 14 has a cam 52 thereon adapted periodically to tilt lever 47 upwardly. The cam engages a leaf spring 53 carried by the lever which is provided with an adjusting screw 54 engaging the spring for varying the height to which the spindle is successively lifted by the cam. The cam serves to effect a positive separation of the pin 44 from the die.

A pulley 50a on shaft 50 drives a pulley 36a on shaft 36 through a belt 51a. Shaft 50 has a pulley 55 thereon driven by a belt 56. The belt 56 is driven by a pulley 57 on a drive shaft 58. The shaft 58 is journaled in bearings carried by spaced posts 59 on table 16 and is driven by any convenient source of power. A pulley 60 on shaft 58 drives belt 46. This belt travels over spaced guide pulleys 61 journaled on a shaft 62 mounted on a supporting leg 62a extending upwardly from table 16 to plate 49. A pulley 63 on shaft 58 drives belt 29 to turn shaft 23.

A solenoid 64 is mounted on a bracket 65 extending upwardly from plate 49. The plunger or core 66 of solenoid 64 has a chain 67 depending therefrom and secured to a book 68 on lever 47. Thus, when the solenoid 

